1. Field of the Invention
This invention relates to a photovoltaic array including a plurality of photovoltaic modules that are mounted on a support surface such as the ground, a ground pad, or a roof, etc. for receiving sunlight to generate electricity.
2. Background Art
An important aspect of manufacturing photovoltaic arrays is the manner in which the photovoltaic modules utilized are manufactured such as disclosed by U.S. Pat. No. 5,248,349 Foote et al., U.S. Pat. No. 5,372,646 Foote et al., U.S. Pat. No. 5,470,397 Foote et al., U.S. Pat. No. 5,536,333 Foote et al., U.S. Pat. No. 5,945,163 Powell et al., and U.S. Pat. No. 6,037,241 Powell et al. In addition to the processing and apparatus utilized to manufacture the photovoltaic modules per se, the mounting and assembly of the modules into an array, which is referred to in the photovoltaic art as xe2x80x9cbalance of systemsxe2x80x9d, is important. Prior art patents involving the balance of systems in the photovoltaic art include: U.S. Pat. No. 4,189,881 Hawley, U.S. Pat. No. 4,760,680 Myers, U.S. Pat. No. 4,966,631 Matlin et al., U.S. Pat. No. 5,092,939 Nath et al., U.S. Pat. No. 5,143,556 Matlin, U.S. Pat. No. 5,316,592 Dinwoodie, U.S. Pat. No. 5,505,788 Dinwoodie, U.S. Pat. No. 5,746,839 Dinwoodie, U.S. Pat. No. 6,061,978 Dinwoodie et al., U.S. Pat. No. 6,065,255 Stern et al. and German Patent Document DE 3611542 Melchoir. The aforementioned U.S. Pat. No. 5,746,839 Dinwoodie patent discloses a photovoltaic assembly having a photovoltaic module with a spacer secured to a lower surface of the module and sized and configured to define an open region beneath the lower surface and access openings formed therein for fluidly coupling the open region to the upper surface with the access openings extending along at least two sides of the photovoltaic module. The aforementioned German Patent Document DE 3611542 Melchoir discloses a photovoltaic array that is mounted on a roof and has photovoltaic modules mounted adjacent each other spaced upwardly from the roof to allow air flow below the modules.
An object of the present invention is to provide an improved photovoltaic array including a plurality of photovoltaic modules for being mounted on a support surface such as the ground, a ground pad, a roof, etc.
In carrying out the above object, the photovoltaic array of the invention includes a plurality of elongated rails for being mounted on the support surface projecting upwardly therefrom and extending in a spaced and parallel relationship to each other. Each rail has an extruded resin construction including a lower base and an upper cap that are secured to each other and cooperate to define a pair of grooves that open in opposite lateral directions from each other. The photovoltaic array also includes rectangular photovoltaic modules having edges that are received by the grooves of the rails so as to be mounted above the support surface in a spaced relationship from the support surface.
The lower base and upper cap of each rail are preferably extruded as separate pieces and secured to each other to define the oppositely opening pair of grooves.
The photovoltaic modules are preferably arranged in pairs with the modules of each pair abutting each other, and each pair of photovoltaic modules is spaced along the elongated lengths of the rails from each adjacent pair of modules to provide openings therebetween. The photovoltaic modules disclosed have elongated rectangular shapes that have lengths about twice as long as widths thereof, and each pair of photovoltaic modules has elongated edges along lengths thereof abutted with each other. Each pair of modules thus has a generally square shape extending between an associated pair of the elongated rails.
The photovoltaic array also includes cross members that extend between the lower bases of the rails to space the rails from each other. These cross members are located within openings between the photovoltaic modules. Electrical wiring of the photovoltaic array is supported by the cross members which have upwardly openings shapes that receive the electrical wiring. More specifically, the cross members have a lower floor and a pair of sides that extend upwardly from the lower floor in a converging shape toward each other and have upper edges that are spaced from each other.
As mentioned above, the elongated rails of the photovoltaic array preferably have the two piece lower base and upper cap construction. In one embodiment, each lower base includes a lower flange for mounting on the support surface, a stem that projects upwardly from the lower flange, and an upper extremity of a T shape that defines an upwardly opening slot extending along the elongated length of the elongated rail. Each upper cap has a T shape including a stem that projects downwardly and is received by the slot in the T-shaped upper extremity of the lower base. Each upper cap also has an upper cross bar that extends in opposite directions from the stem thereof to cooperate with the T-shaped upper extremity of the lower base in defining the pair of grooves that open in opposite directions from each other to receive edges of the photovoltaic modules that are mounted by the rails on the support surface.
The upper extremity of the lower base of each rail has a pair of upwardly projecting stops respectively located on opposite sides of the slot to position the modules horizontally with respect to the rails.
The elongated rails have the lower flange of the lower base provided with a greater lateral width along the elongated length thereof than the T-shaped upper extremity of the lower base and the upper cross bar of the upper cap. Also, the stem of the lower base has scallops for reducing the resin utilized.
In an alternate embodiment of the two piece rail construction, the lower base has a lower end for mounting on the support surface, a stem that projects upwardly from the lower end, an upper extremity of a T shape that defines an upwardly opening slot extending along the length of the elongated rail, and the upper extremity of the lower base includes downwardly extending flanges for securing flashing.
Fasteners secure the upper cap of the two piece rail construction to the lower base of the rail, and the upper cap includes an elongated extruded formation that facilitates centering alignment of drilled holes for receiving the fasteners.
The photovoltaic array has the lower bases and the upper caps of the two piece elongated rails extruded from a first resin and has the grooves of the rails provided with pads of a second material that is softer than the first resin to accommodate for thickness variations. More specifically, the lower base is extruded entirely from the first resin and the upper cap is coextruded from the first resin and a second resin which constitutes the second material that provides the pads which are located on the upper cross bar within the grooves.
In another embodiment of the two piece rail construction, the upwardly opening slot of the lower base and the downwardly projecting stem of the upper cap have connection formations for providing securement of the upper cap to the lower base.
The cross members of the photovoltaic array are supported by and extend between the T-shaped upper extremities of the lower bases of the rails within openings between the photovoltaic modules to space the rails from each other. These cross members have elongated shapes extruded from resin within an upwardly opening shape and, as previously mentioned, electrical wiring is received by the upwardly opening cross members.
In one use disclosed, the photovoltaic array has its support surface embodied by a roof having a membrane on which the rails are mounted. It is also possible to utilize connections that secure the lower bases of the rails to the membrane of the roof. These connections can be embodied by bonds between the lower bases of the rails and the membrane on the roof, and the bonds between the lower bases of the rails and the membrane on the roof can be autogenous. The connections can also include connector sleeves that slidably receive the lower bases of the rails, and this construction of the connections also includes bonds that secure the connector sleeves to the membrane on the roof. More specifically, the connector sleeves are made of the same material as the membrane on the roof, and the bonds between the connector sleeves and the membrane on the roof are autogenous. In another embodiment, the connections include elongated connector strips, the lower bases of the rails have openings through which the connector strips extend, and the connector strips have ends secured to the membrane on the roof. More specifically, the connector strips are made of the same material as the membrane on the roof and the ends of the connector strips have autogenous bonds that provide the securement to the membrane on the roof.